1. Field of the Invention
The present invention relates to an automotive information display device for displaying various information required on an automobile and, more particularly, to an automotive information display device incorporating a liquid crystal display unit.
2. Description of the Related Art
Conventionally, various meters or indicators such as speedometers, tachometers, travelling range meters are installed on instrument panels of automobiles. Recently, however, there is an increasing demand for a wider variety of information to be displayed, such as the result of a self-checking just before starting, traffic guide information which is to be given when the automobile has approached a crossing, a road map with or without indication of a desired route on the map, and so forth.
In general, display devices or indicators are required to have a large display area to enable various types of information to be displayed in a manner which facilitates recognition. Unfortunately, however, it is difficult to find sufficient space for installing a large display panel in the restricted area around the driver's seat or an the instrument panel. In addition, a display panel having such a large display area not only restricts the field of vision but also hampers the driving.
Various proposals have been made for the purpose of overcoming this problem. For instance, Japanese Patent Unexamined Publication No. 62-72831 discloses a display system having a cathode ray tube (CRT) installed in the instrument panel of an automobile, such that the display screen of the CRT is directed towards an aperture formed in the upper surface of the instrument panel. The image on the CRT screen is reflected and projected by a mirror which is set at the opening at a predetermined angle. Japanese Patent Unexamined Publication No. 61-282139 discloses a system employing a liquid-crystal type electronic display panel which is retractably received in a recess formed in the instrument panel.
The system incorporating a CRT, however, encounters the difficulty of reducing the size of the CRT, in particular the size measured in the direction normal to the screen to accommodate the CRT in the dashboard. In consequence, the CRT undesirably restricts the space for installation of an air-conditioner duct and other instruments even if the CRT is installed with its screen directed upward.
On the other hand, the system employing the liquid-crystal type electronic display panel has a small thickness and can advantageously be installed in the recess of the instrument panel in a retractable manner. In addition, the panel can be set such that the display surface is directed obliquely upward so as to improve the viewing angle characteristic in the vertical direction to some extent. Unfortunately, however, no specific consideration is given for the purpose of improving the viewing angle characteristic in lateral directions.
In general, information displayed on an automotive instrument panel is to be read by the driver or a passenger assisting the driver. Therefore, when a liquid-crystal type device is used, it is necessary to improve the viewing angle characteristic of the liquid crystal as much as possible.